Hot-air furnace



2 Sheets-Sheet 1.

J. H. NEVINS. HOT AIR FURNACE.

(No Model.)

Patented Apr. 29, 1890.

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2 Sheets-Sheet 2'.

(No Model.)

J. H. NEVINS.

HOT AIR FURNACE.

No. 427,006. Patented Apr. 29, 1890.

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Nrrnn STATES E ATENT .FFrcE.

HOT-AIR FU RNAC E.

SPECIFICATION forming part of Letters Patent No. 427,006, dated April29, 1890.

Application filedJnne 15, 1889. Serial No. 314,478. (No model.)

T0 at whom it may concern:

Be it known that 1, JOHN H. NEVINS, a citizen of the United States,residing at Minneapolis, in the county of Hennepin and State ofMinnesota, have invented new and useful Improvements in l-Iot-AirFurnaces; and I do hereby declare the following to be a full, clear, andexact description of said invention, reference beinghad to theaccompanying drawings, and to the letters of reference marked thereon,which form a part of this specification. v

This invention relates to certain improvements in hot-air furnaces forheating purposes; and it has for its objects to provide for the perfectcombustion of the fuel by means of a downward draft of air into thecombustion-chambers of the furnace, so that the inflammable gasesarising from the fuel therein, as well as the fuel, may be perfectlyconsumed on a slow or rapid principle, as more fully hereinafterexplained.

My invention consists, essentially, in a fu rnace, a singlefire-chamber, and a central vertical eduction-flue extending through it,or having a series of fire-chambers arranged at proper intervals arounda central eductionfine, and communicating therewith by means of a seriesof lines leading from the upper parts of said fire-chambers to the saideduction-flue, inconnection with an air-chamber surrounding all of thefire-chambers and the fines leading therefrom, the said fire chambersand the fiues being entirely surrounded by a coldair chambercommunicating with the hot-air chamber by means of apertures through itsbottom, and the hot air chamber being provided with reduction-passages,through which the hot air may be carried off through suitable flues tovarious points to be used.

The above-mentioned objects are attained by the means illustrated in theaccompanying drawings, in which- Figure 1 represents a horizontalsectional View, taken on the line X X of Fig. 2, showing a furnaceconstructed according to my invention. Fig. 2 represents a sideelevation of the furnace with a portion of the lower part broken away,so as to show the fines by means of which the air is drawn from therespective floors of a building into or through the furnace. Fig. 3represents a transverse vertical sectional View of the furnace, taken onthe line y g of Fig. 1. Fig. at represents a sectional. view of one ofthe feed devices through which fuel is introduced to the fire-chamberand air is admitted downwardlyinto the combustion-chamber thereof. Fig.5 represents ahorizontal sectional view showing a modification'of thefire-chamber. Fig. 6 represents a vertical sectional view of amodification. Fig. 7 indicatesa sectional view of the central dome andgrate. Fig. 8 represents a horizontal sectional view of a modificationof the furnace, showing the same constructed with a single fire-chamber;and Fig. 9 is a transverse vertical sectional view of said modification.

Referring to the drawings, dicates the external shell or casing of thefurnace, which is cylindrical in shape, preferably, and constructed ofany suitable material.

WVithin the shell A and concentric there with an inner shell B, of lessdiameter than the external shell, is located, an intervening space 0being left between the two shells, which forms a-cold-air passage, whichconnects with the external air by means of airducts E entering atsuitable points near the top of the air-space. The bottom of theinternalshell is elevated above the bottom of the external shell, leaving anintermediate space D, which connects with the space 0 before mentioned,and the said bottom of the the letter A inthe grates are located theash-pits G, provided with door-openings H through the external shell ofthe furnace. The upper ends of the fire-boxes are inclosed by means ofplates I, which have openings from which extend upwardly the feed-tubesK, which pass through the crown of the furnace and terminate in theplane thereof, the said tubes being pro vided withperforated covers L,through which air passes to insure complete combustion in thecombustiolrchambers, the said covers be ing removable for the purpose ofcharging fuel into the fire-pots. Vithin the feed-tubes are locatedinternal tubes M, which are made flaring at their upper and lower ends,the upper ends being larger than the lower ends and fittingin the upperpart of the feed-tubes, to which they are fastened in any suitablemanner, The lower ends of the said internal tubes extend below the lowerends of the feedtubes into the upper parts of the combustionchambers,the object being to permit the gases, as they flash upward when thecover is removed, to pass up between the internal and external tubes andprevent the flame from flashing up through the feed-tube.

The letter N indicates an annular flue or chamber located within theinner shell around the upper portions of the fire-chambers, and withsaid annular chamber the upper parts of the fire-chambers are connectedby means of radial flues P, so that the products of combustion may passfrom the fire-chambers into said annular chamber.

The letterR indicates a flue extending centrally from near the bottomthrough the crown of the furnace and connecting with a suitable chimneyorstack. From the annular flue, before mentioned, extend downwardly theflues S, which are bent inwardly at about right angles, and connect withthe central fine R near its lower end, the connecting ends of the finesbeing gradually contracted, as shown in Fig. 3 of the drawings.

T indicates a Vertical flue concentric with and surrounding the flue R.The said flue T extends from a point below the bottom of the furnace upinto the furnace, terminating in a dome U at the center of the crown ofthe furnace. The said flue T is provided with a chamber V at its lowerend, into which enter a series of fines or tubes XV, extending from thevarious floors or apartments of the building in which the furnace islocated for the purpose of ventilating the same. As shown in Fig. 3, theair drawn through the flue T and the tubes XV enters the heating-chamberof the furnace and is heated for further use.

In the modification in Figs. (3, 7, and S of the drawings the grate ofthe furnace is provided with a hollow cone V, which rises from thecenter of said grate vertically into the firechamber, being perforatedat its apex, so as to admit air from below above the bed of fuel in thefire-box to insure perfect combustion in the combustion-chamber.

In the modification shown in Figs. 9 and 10 a single fire-chamberconcentric with and surrounding the central eduction line is shown. Ineach of the latter instances, however, the general arrangement of theheating-tines connecting with the central eduction-flue is the same asshown in Figs. 2 and 5, the products of combustion being carried upcentrally through the furnace and the combustion in thecombustion-chamber being maintained by a downdraft or a draft of airentering above the bed of fuel in the fire-pot.

The hot-air chamber at suitable points is provided with eduction-finesX, through which the hot air maybe passed off to suitable places foruse.

The operation of my invention will be clearly understood from the abovedescription, in connection with the drawings, in which the course of theair for supporting combustion, the products of combustion, and the coldand heated air is shown by arrows.

Having thus described my invention, what I claim, and desire to secureby Letters Patent, is-

1. In a furnace, the combination, with the fire-pot and combustion-chamber thereof, havin g a downward draft opening into thecombustion-chamber, of a central eduction-flue passing vertically upthrough the furnace, and fines connecting the upper part of thecombustion-chamber with the bottom of said central flue, substantiallyas and for the purpose specified.

2. In a furnace, the combination of a central eduction-flue, a series offire-chambers grouped around said central flue, and a series of linesconnecting the upper parts of the fire-chamber with the lower part ofthe connecting-flues, whereby the products of 001m bustion are carriedoff from the furnace, substantially as specified.

In a furnace, the combination of a firechamber located therein, a seriesof fines and a central eduction-flue, said series of fiucs connectingthe upper part of the combustion chamber with the lower part of saideductionflue, a cold-air chamber surrounding the firechamber and fines,and cold-air-induction fiues leading to said chamber, substantially asand for the purpose specified.

i. In a furnace, the combination of a firechambcr, a centraleduction-flue connected with the combustioil-chamber thereof,aheating-chamber, and a concentric air-flue surrounding the centraleduction-flue having airinductions at its lower end and connecting withthe heating-chamber at its upper end, whereby the air from a buildingmay be witlr drawn and heated for subsequent use, substantially asspecified.

5. I11 a furnace, the combination of the external shell, a concentricinternal shell forming an intervening cold-air space, a series offire-chambers, an annular flue connecting therewith, a series ofdownwardly-extcnding fines, and a central eduction-flue with which thesaid fines are connected at its bottom,

whereby the products of combustion are car- In testimony whereof I afiixmy signature in 10 l ried off through the center of the furnace, thepresence of two subscribing witnesses.

, substantially as specified.

6. The combination, in a furnace having a JOHN H. NEVINS.

5 central eductio'n-flue, of a firechamber located therein, and a gratehaving a central Witnesses: conical dome extending Vertically into thefire- H. M. STERLING, pot of the chamber, and a downward draft L. W.SINSABAUGH. opening at the top, substantially as specified.

